1. Field of the Invention
This invention relates to a memory bandwidth control device and, more particularly, is suitably applied to a memory bandwidth control device for temporarily storing in a memory material data such as video and audio, which is externally entered to a video editing apparatus, and then processing the material data via the memory or performing memory bandwidth control for a burst transfer to a hard disk drive.
2. Description of the Related Art
To store material data received from an external device via an input/output port in a hard disk drive, a video editing apparatus temporarily stores the material data by a prescribed amount or more in a memory and then performs a burst transfer of the data to the hard disk drive, so as to transfer data in a short time with improved transfer efficiency.
Further, to edit material data, the video editing apparatus gives material data being stored in the hard disk drive, to an external device such as an effector via the memory, to edit the data, and then performs the burst transfer of the edited material data via the memory, thereby storing it in the hard disk again or outputting them to the outside.
As described above, the video editing apparatus communicates material data with the hard disk drive via the memory. Therefore, memory bandwidth should be controlled between the memory and a plurality of external devices being connected to the video editing apparatus via input/output ports.
In a case where memory bandwidth (bit width×clock number) is 100 Mbps and there are 10 external devices, the video editing apparatus equally divides the memory bandwidth by the number of the external devices simply, resulting in assigning 0.1 second to the devices with time division (10 Mbps).
By the way, such a video editing apparatus assigns fixed memory bandwidth to each external device being connected thereto via an input/output port, by means of time division. Therefore, the number of external devices to be connected is limited according to the memory bandwidth. In addition, bandwidth assigned external devices which do not receive and output material data is useless, resulting in deteriorated data transfer efficiency.